Carrier tracking system

ABSTRACT

An infrared tracker for tracking a carrier in clutter comprises a pyrotechnically heated emitter, a beam concentrator, and a blanking means all of which are mounted on the carrier, and a command link, a thermal detector, a display signal storage means, a display, and a comparator all of which are located remotely to the carrier, said command link operative to provide an emitter start-up signal and a blanking command signal, said emitter and blanking means operative in response to the command signals sent to the carrier when there is clutter present that might be confused with the carrier, respectively, to actuate the emitter and blanking means, said display storage means operative to store a first video frame of the carrier while the emitter is blanked out, and said comparator for comparing the first video frame without the emitter to a subsequent video frame including the emitter to distinguish between the clutter and the carrier.

This invention relates to an infrared carrier tracking, and moreparticularly to a system for tracking the carrier through clutter.

In the past guidance techniques, such as those disclosed in U.S. patentapplication, Ser. No. 896,087, filed Apr. 13, 1978 for a "MissileDetecting and Tracking Unit", have provided some clutter immunity asfollows. During the early portion of the carrier flight, the carrierengine, if it has one and if not a beacon, is the brightest object inthe detector field of view; all clutter objects have less intenseimages. The size and location of the clutter is stored so that it willnot become confused with the beacon during the latter portion of flightwhen the carrier engine image is dim. In addition, a two dimension trackgate is placed about the carrier to gate out any clutter. The gate ismade just large enough to contain the portion of space into which thecarrier is moving; as the carrier moves away, the gate is narrowed toeliminate widely scattered clutter. Nevertheless, when a moving carrieris tracked, new clutter is brought into the field view. Further, aspectangles of the clutter during the flight can change and clutter locationcan change due to operator jitter.

Accordingly, it is an object of this invention to provide for reliable,effective tracking of a carrier through clutter.

Another object of the invention is to provide a tracking system having aheat source whose intensity is controllable at short range to avoidblooming and to effect smoke penetration at long range.

Still another object of the invention is to provide a tracking systemhaving clutter cancellation while tracking the carrier.

Yet another object of the invention is to provide a tracking systemwhose sub-system aboard the carrier is highly efficient and reliable,yet economical to produce using mass production techniques.

Briefly stated the invention comprises a tracking system which includesa beacon sub-system mounted upon a carrier, and a beacon controlsub-system located remotely to the carrier. When a clutter ambiguityenters the field, the control sub-system sends a beacon interrupt signalto the beacon sub-system to interrupt the beacon. The resulting videoframe is stored for comparison with a subsequent video frame taken withthe beacon emitting energy. The subsequent frame is compared with theprevious frame and the comparison reviewed to determine the location ofthe beacon. Any clutter present will be in both frames; however, thebeacon will be present in only one frame. By this technique the clutteris differentiated from the carrier.

The novel features characteristic of the embodiments of the inventionmay best be understood by reference to the following detaileddescription when read in conjunction with the accompanying drawingswherein;

FIG. 1 depicts the utilization of a combined infrared sight and trackerunit;

FIG. 2 is an isometric view of the carrier including the beacon shuttersystem;

FIG. 3 is an isometric view of the beacon shutter system;

FIG. 4 is an isometric view of the shutter drive having a portion of thehousing broken away to show more clearly the shutter drive mechanism;

FIG. 5 is a fragmentary cross sectional view of the thermal beacon takenalong line A--A of FIG. 3;

FIG. 6 is a schematic view of the shutter-signal separation circuit andpower driver of the shutter electronics;

FIG. 7 is a schematic of the beacon/carrier interface; and

FIG. 8 is a simplified flow diagram of the infrared sight and trackerunit.

For purposes of description and not by way of limitation the inventionshall be described in connection with a guided missile used as thecarrier. Such a guided missile is shown in FIG. 1 in which an infraredsight and tracker unit 10 comprises a missile 12 which has been launchedfrom launcher 14 toward its destination or target 16. The target isshown as a tank viewed through the visual sight. It could also have beenviewed through the infrared sight at the gunner's option. A beacon 18 isattached to the aft end of the missile 12. The beacon 18 is a part ofthe beacon system described hereinafter. A sighting means 20 which maybe, for example, a thermal night sight such as that manufactured byTexas Instruments Incorporated under the designation AN/TAS4 NightSight, is attached to the launcher 14 for viewing and tracking thecarrier 12. The night sight is a forward looking infrared receiver andimaging device which includes a linear array of infrared detectors forscanning a field of view to detect the thermal energy emitted from thecarrier's beacon. The night sight is modified, as hereinafter described,to accommodate a beacon control sub-system.

Each detector of the sighting means together with its preamplifierconstitutes a channel (not shown) connected to an electronics package22. A controller 24 controls the launching of the missile, activation ofthe night sight infrared receiver and activation of the beacon trackerunit. The electronics package 22 includes a microprocessor, which ispreferably a Texas Instruments Incorporated SBP9900 microprocessor,controlled by the controller 24.

The carrier missile 12 (FIG. 2) includes a beacon system 26, a housing28, an electronics pod 30 attached to the housing, an umbilicalconnector 32, and ballast 34 attached to the faring 36. The housing 28has an aft end to which the beacon system is attached and a body portionto which the electronics pod 30 is attached. The electronics pod 30contains the electronics for the beacon system. The umbilical connector32 connects the electronics pod 30 to the beacon system 26. The ballast34 attached to the faring 36 is to maintain the center of gravity orbalance of the carrier owing to the weight of the beacon system.

Referring now to FIG. 3, the beacon system comprises a housing 38, apyrotechnic igniter 40, a squib hammer 42, a shutter actuator 44,shutter drive linkage 46, a shutter return spring 48, installation hooks50, and an installation bracket 52. The housing 38 is attached to themissile housing 28 (FIG. 2) by the bracket 52 and hooks 50. The housing38 includes a case 54 FIG. 5 having an open end covered by a frangibleglass cover 56. The case 54 may be, for example, a cast carbon typecase. The frangible glass cover is shattered for removal by the squibhammer 42 (FIG. 3). A layer of non-combustible insulation material 58(FIG. 5) covers the bottom of the case. A pyrotechnic heater 60 ishermetically sealed in foil 62 for protection during storage. Thepyrotechnic heater may be selected from the group of intermetallicreaction pyrotechnic materials consisting of titanium boride, titaniumboride plus titanium carbide, titanium carbide, zirconium boride, andzirconium carbide. The foil 62 is a heat meltable foil which melts whenthe pyrotechnic heater is ignited thereby enhancing the thermal path toan emitter 64. The emitter 64 is, for example, a carbon type emittercapable of withstanding the high temperature (3800° C.) effects.

An apertured base plate 66 covers the emitter 64. An apertured sheet 68is slidably mounted in base plate guides between the apertured baseplate 66 and an apertured honeycomb optics 70. The aperture sheet 68acts as a shutter for obscuring the apertures of the base plate 66 andhoneycomb optics 70, which are in alignment, when displaced by about 1/2the hole spacing. The apertured sheet or shutter 68 has two flexures 48and 74 at opposite ends (FIG. 4). Flexure 48 acts as a return spring tohold the shutter 68 open, i.e. the aperture sheet holes are aligned withthose of the base plate and honeycomb optics. Flexure 74 acts as atransfer lever to the drive linkage 46.

The drive linkage 46 includes a rod 76 having, for example, ball shapedends. The ball shaped ends of rod 76 extend, respectively, through slotsin flexure 74 and one arm of a slotted flexure-pivoted bell crank 78.The other arm of the flexure-pivoted bell crank is attached to the core79 of a linear solenoid comprising the shutter actutor 44. Thus, withthe return spring 48 pulling the aperture sheet and the linear solenoidpulling the shutter drive linkage to close it the system always acts intension thereby utilizing the tensile strength of the member tosubstantially reduce the size of the members.

The shutter electronics 30 (FIG. 2) comprises a shutter-signalseparation circuit and power driver packaged separately from the beaconto fit the available space and reduce mass unbalance in the missile. Apower source such as, for example, the existing missile battery 80 (FIG.6) provides power to a dc regulator 82 and power driver 84. The dcregulator provides selected dc voltages to a buffer amplifier 86, 2-polelow pass filter 88 and threshold detector 90. The buffer amplifier 86reestablishes the values of the guidance and beacon actuator signalsreceived by the missile. The two-pole, low pass filter, with apreselected corner frequency rejects the missile steering commands andpasses the shutter actuating dc pulse. The dc shutter pulse signaltriggers a threshold detector 90 which drives the power driver outputstage 84. The power driver contact is connected to the shutter actuator44 solenoid (FIGS. 3 & 4). The command pulse duration is selected tokeep the shutter closed for an interval equal to one time frame of thenight sight.

The beacon/missile interface electronics (FIG. 7) comprises the powersource 80 which is connected to the junction of the shutter driveelectronics pod 30, fusible link 92 of a pyrotechnic initiator branchcircuit, and switch 94 of a squib hammer branch circuit. The pyrotechnicinitiator branch circuit, in addition to the fusible link 92 includes apyrotechnic initiator 96, which is, for example, an electrically firedheat match. The squib hammer branch circuit includes, in addition to theswitch 94, a fusible link 98 connected to the switch 94 and to a squib100. The fusible links 92 and 98 are included in the heater ignition andcover removal circuits to protect the battery from potentialoverloading.

At start up, the squib of the squib hammer circuit is fired electricallyand the gas generated drives the hammer 102 which is a low brisancepyrotechnic hammer. The cover 56 being a chemically tempered glasshaving a thickness of about 0.050 to 0.060 inch and a modulus of ruptureof about 40,000 psi. is fragmented and removed by the hammer withinabout 10 milliseconds. Also at start up the beacon or heater is fired.The heater pyrotechnic has a propagation velocity such that the time forthe reaction to spread to the entire source is comparable to themissile's flight time. Thus, the emitter 64 (FIG. 5) first meets theneed for lower intensity early in flight and is gradually raisedthroughout the flight to meet the higher intensity need during the laterstages of flight.

As previously described the shutter drive electronics 30 (FIG. 2)controls the actuation of the shutter actuator 44 solenoid (FIG. 3).Standby power for the shutter electronics 30 is low (about 1 watt). Whenshutter operation is commanded, each cycle draws up to about 10watt-seconds.

Shutter operation, if it occurs at all, will happen near the end of theflight. The microprocessor of the electronics package 22 (FIG. 1) isprogrammed (FIG. 8) so that upon receipt of a start up signal 104tracker conditioning 106 is effected by starting the clock, timingsequence and determining pre-fire conditions. A time decision 108 isthen made. If the time is less than a preselected time, a decision 110is made whether the tracker is in handoff. Handoff results when thetracker looses the missile. If the answer is no the computer commandsthe missile to fly a standard track link 112, and the computer returns114 to start 104. If the tracker is in handoff, a decision 116 is madewhether the missile is in the field of view of the forward lookinginfrared (FLIR) sight. If not, a command 118 is given for the missile tofly a preprogrammed flight profile. Next a command 120 is given toactivate a GLI tracker for missile acquisition and the computer returns122 to start 104. If the missile is in the field of view a command 124is given to compute the centroid area of the last field and basedthereon to compute a position estimate. The computer then returns 126 tostart.

When the decision 108 is that the preselected time has been reached,commands 128 and 130 are given to establish, respectively, scenestabilization and a peak set. Next a command 132 is given to establish aclutter map reference from the stabilized scene. Then a command 134 isgiven to reject peaks in the clutter maps by comparing the establishedpeaks with the clutter map reference. Next a command 136 is given toupdate the clutter map. Then a decision 138 is made whether any peakremains. If no peak remains a command 140 is given for the tracker tocoast and then return 142 to start 104. If yes, a decision 144 is madewhether more than one peak exists within a reasonable radius of theprevious missile track. If only one peak exists, a command 146 is givento compute the centroid area which is converted to guidance signals.Then the computer returns 148 to start. If more than one peak exists, acommand 150 is given to actuate the beacon shutter system, and thebeacon shutter 68 is closed for one video frame. All peaks appearing inthe map during this frame are known to be clutter and are entered in theclutter map. The beacon is then turned on again and the computerreturned 152 to the start.

Although only a single embodiment of this invention has been describedherein, it will be apparent to one skilled in the art that variousmodifications to the details of construction shown and described such asfor example, substituting a laser (CO2 laser) for the pyrotechnic, maybe made without departing from the scope of the invention.

What is claimed is:
 1. A carrier tracking method for detecting,tracking, and guiding a missile having a beacon thereon comprising:(a)establishing an image of a first selected scene including only clutter;(b) establishing the peaks of a second scene including clutter and thebeacon; (c) stabilizing the second scene with respect to the firstscene; (d) comparing the stabilized image of the second scene with thepeaks of the first scene; (e) eliminating the peaks in both scenes whichcorrespond to each other; (f) if more than one peak remains, selectivelyactivating a blanking means to remove the peak produced by the beacon;(g) identifying as clutter any remaining peaks in the scene; and (h)activating the blanking means to return the beacon to the scene.
 2. Acarrier tracking method for detecting, tracking, and guiding a missilehaving a beacon thereon .Iadd.with a system which tracks the missilewithin a field of view, the method .Iaddend.comprising:(a) issuing acommand signal to launch the missile and activate the beacon; (b)issuing a command signal to acquire the missile for tracking; (c)determining whether the .[.missile.]. tracking system has lost themissile and is in hand off; (d) determining whether the missile is inthe .[.missile.]. tracking system field-of-view; (e) establishing animage of a first selected scene including only clutter to form a cluttermap reference; (f) establishing the peaks of a second scene includingclutter and the beacon; (g) stabilizing the second scene with respect tothe first scene; (h) comparing the clutter map reference with theestablished peaks of the first scene and .[.update.]. .Iadd.updating.Iaddend.the clutter map; (i) eliminating the peaks in both scenes whichcorrespond to each other; (j) if more than one peak remains, selectivelyactivating a shutter to remove the beacon from the scene; (k)identifying the remaining peaks as clutter; and (l) activiating theshutter to return the beacon to the scene.
 3. A carrier tracking systemfor detecting, tracking and guiding a carrier to a destinationcomprising:(a) guidance means mounted on the carrier for guiding thecarrier; (b) guidance control means positioned off the carrier, saidguidance control means operative to provide guidance signals to theguidance means; (c) a beacon system, said beacon system including abeacon subsystem mounted on the carrier and a beacon detector andcontrol subsystem positioned off the carrier, said beacon subsystemmounted on the carrier includes a beacon and means for blanking out saidbeacon and said beacon detector and control subsystem includes a thermaldetector for mapping thermal energy emanating from a scene whichincludes clutter and said beacon, means for establishing thermal peaksin the scene corresponding to the clutter and the beacon, comparatormeans for comparing the map of thermal energy with the thermal peaks,means for selectively operating the blanking means to blank out thebeacon to determine clutter and beacon identification; and (d) means fordetermining guidance signals from the beacon detector and controlsubsystem for the guidance control means.
 4. A carrier tracking systemaccording to claim 3 wherein the beacon is a pyrotechnic heater.
 5. Acarrier tracking system according to claim 3 wherein the beacon is alaser.
 6. A carrier tracking system according to claim 5 wherein thelaser is a CO₂ laser.
 7. A carrier tracking system according to claim 3wherein the beacon is a pyrotechnic heater and the means for blankingout said beacon includes a shutter for selectively interrupting beaconemission.
 8. A carrier tracking system according to claim 3 wherein thebeacon is a laser and the means for blanking includes a means forselectively turning the laser on and off.
 9. A carrier tracking systemaccording to claim 4 wherein the beacon subsystem further includes anemitter mounted on a major surface of the pyrotechnic heater.
 10. Acarrier tracking system for detecting, tracking and guiding a carrier toa destination comprising:guidance means mounted on the carrier forguiding the carrier, guidance control means positioned off the carrier,said guidance control means operative to provide guidance signals to theguidance means, a beacon system, said beacon system including a beaconsubsystem mounted on the carrier and a beacon detector and controlsubsystem positioned off the carrier, said beacon subsystem comprising abeacon and means for blanking out the beacon and said beacon detectorand control subsystem including a thermal detector for sensing thethermal energy emanating from a scene which includes clutter and saidbeacon, means for selectively operating the blanking means to blank outthe beacon such that the thermal detector senses only the clutter fromsuch scene, comparison means for comparing the scene with clutter onlyto the scene with clutter and the beacon to distinguish the beacon fromthe clutter, and means for determining guidance signals from the beacondetector and control subsystem for the guidance control means.
 11. Acarrier tracking system according to claim 10 wherein the beacon is apyrotechnic heater.
 12. A carrier tracking system according to claim 10wherein the beacon is a laser.
 13. A carrier tracking system accordingto claim 10 wherein said beacon is a pyrotechnic heater and said meansfor blanking is a shutter for selectively interrupting beacon emission..Iadd.
 14. A carrier tracking method for detecting, tracking, andguiding a missile having a beacon thereon comprising:(a) establishing animage of a first selected scene including only clutter; (b) establishingthe peaks of a second scene including clutter and the beacon; (c)eliminating the peaks in both scenes which correspond to each other; (d)if more than one peak remains, selectively activating a blanking meansto remove the peak produced by the beacon; (e) identifying as clutterany remaining peaks in the scene; and (f) activating the blanking meansto return the beacon to the scene. .Iaddend. .Iadd.
 15. A carriertracking method for detecting, tracking, and guiding a missile having abeacon thereon with a system which tracks the missile within a field ofview, the method comprising:(a) issuing a command signal to launch themissile and activate the beacon; (b) issuing a command signal to acquirethe missile for tracking; (c) establishing an image of a first selectedscene including only clutter to form a clutter map reference; (d)establishing the peaks of a second scene including clutter and thebeacon; (e) comparing the clutter map reference with the establishedpeaks in the first scene and updating the clutter map; (f) eliminatingthe peaks in both scenes which correspond to each other; (g) if morethan one peak remains, selectively activating a shutter to remove thebeacon from the scene; (h) identifying the remaining peaks as clutter;and (i) activating the shutter to return the beacon to the scene..Iaddend. .Iadd.
 16. A system for detecting and tracking a carrier onroute to a destination wherein a radiation transmitting system mountedon the carrier includes a beacon and means for blanking out the beaconin order to selectively transmit radiation to a radiation detectorpositioned to map energy emanating from a scene which includes thecarrier and provide frames of video data corresponding to the scene,said system for detecting and tracking comprising:input circuitry forreceiving video data; output circuitry to provide control data to thecarrier; means, coupled to the input circuitry, for identifying peaks ina first frame of video data which correspond to the beacon and clutterpresent in the scene; means, coupled to the output circuitry, forblanking out beacon radiation in order for the input circuitry toreceive video data from a second frame that does not include a peakcorresponding to the beacon; and means for comparing the first andsecond video frames and identifying peaks in the second frame asclutter. .Iaddend. .Iadd.17. The system of claim 16 further includingmeans, coupled to the output circuitry, for providing carrier guidancesignals based on a comparison of the first and second video frames..Iaddend. .Iadd.18. The system of claim 16 wherein peaks identifiable inthe first and second frames correspond to thermal energy detectable withan infrared night sight. .Iaddend. .Iadd.19. The system of claim 16wherein the blanking means provides control signals for mechanicallyshuttering a beacon formed with a pyrotechnic heater. .Iaddend..Iadd.20. The system of claim 16 further including means for defining atrack gate about the beacon image in a segment of video data as thecarrier approaches the destination and wherein said track gate serves toisolate the beacon image from clutter. .Iaddend. .Iadd.21. The system ofclaim 16 formed as:an electronics package comprising a microprocessorand adapted for coupling to a radiation detector; and a controller whichcontrols launching of the carrier, activation of the detector andactivation of said means for comparing the first and second videoframes. .Iaddend. .Iadd.22. A guidance processing and control system fortracking a carrier in the presence of clutter, said carrier including abeacon system for selectively transmitting radiation based on remotecontrol signals, said processing and control system capable of trackingthe carrier in conjunction with a sight and electronics of the typewhich outputs frames of video data based on energy emanating from ascene that includes the carrier, said system comprising:processingcircuitry positioned off the carrier for tracking and guiding thecarrier and for selectively controlling transmission of radiation fromthe beacon system to the sight; and a storage medium containinginformation to correlate signal peaks in different frames of the videodata and criteria for selectively controlling transmission of radiationfrom the beacon system to the sight, said processing circuitry coupledto receive said information from the storage medium to (a) generate areference map based on the video data, (b) compare peaks in a secondframe of the video data with peaks in the reference map, and (c)selectively control transmission of radiation to the sight. .Iaddend..Iadd.23. The system of claim 22 wherein the sight is a thermal nightsight responsive to infrared radiation. .Iaddend. .Iadd.24. The systemof claim 22 wherein said processing circuitry comprises digitally basedsemiconductor electronics which provides signals for tracking thecarrier. .Iaddend. .Iadd.25. The system of claim 22 wherein saidprocessing circuitry is formed as: an electronics package comprising amicroprocessor and adapted for coupling to the sight; and a controllerwhich controls launching of the carrier, activation of the sight andcomparison of peaks. .Iaddend. .Iadd.26. The processing and controlsystem of claim 22 operable with a beacon system of the type whichincludes a radiation source in combination with a mechanical shutter andwherein transmission of radiation to the sight is controlled byproviding signals which effect movement of the mechanical shutter..Iaddend. .Iadd.27. The processing and control system of claim 22wherein said processing circuitry operates to distinguish clutter fromradiation transmitted from the beacon system by identifying clutter in asegment of video data acquired during a period when radiation is nottransmitted from the carrier to the sight. .Iaddend. .Iadd.28. Theprocessing and control system of claim 22 wherein said processingcircuitry, when operating in conjunction with said storage medium,serves to define a track gate about an image corresponding to beaconradiation, said gate formed in segments of video data as the carrierapproaches the destination to isolate the beacon image from clutter..Iaddend. .Iadd.29. A digital processing system for tracking and guidinga carrier which includes a beacon system for transmitting radiation,based on remote control signals, to instrumentation of the type whichoutputs frames of video data indicative of a scene, said processingsystem comprising:input circuitry for receiving frames of video dataoutput by the instrumentation and corresponding to imaged scenescontaining the carrier; output circuitry for providing control signalsto the beacon system in order to transmit radiation to theinstrumentation; and data processing circuitry coupled to said input andoutput circuitry for (a) selectively providing the control signals totransmit radiation from the beacon system to the instrumentation and (b)comparing peaks in different frames of video data to identify data in avideo frame which corresponds to the carrier. .Iaddend. .Iadd.30. Thesystem of claim 29 wherein said selective provision of control signalsby said data processing circuitry is based on identification of apredetermined condition discernable from the video data. .Iaddend..Iadd.31. The system of claim 30 wherein the predetermined conditioncorresponds to identification of more than one peak in a frame of videodata which results after comparing or eliminating peaks in the differentvideo frames which correspond to one another. .Iaddend. .Iadd.32. Thesystem of claim 29 wherein said data processing circuitry includesdecision-making criteria, representable in the form of digitalinformation, for selectively transmitting radiation from the beaconsystem to the instrumentation. .Iaddend. .Iadd.33. The system of claim29 wherein said data processing circuitry includes instructionalinformation for correlating a peak in a segment of data with the carrierby first identifying, as clutter, one or more peaks in a second segmentof data acquired during a period when the instrumentation is notreceiving radiation from the beacon system. .Iaddend. .Iadd.34. Thesystem of claim 29 wherein said data processing circuitry is responsiveto the presence of a clutter ambiguity in one of the scenes, saidcircuitry providing said output circuitry with a control signal forinterrupting transmission of radiation from the beacon system to theinstrumentation. .Iaddend. .Iadd.35. The system of claim 34 wherein saidprocessing circuitry stores a segment of video data acquired during aperiod when radiation from the beacon system to the instrumentation isinterrupted in order to compare peaks in said segment of data with peaksin a segment of data associated with a different video frame. .Iaddend..Iadd.36. A guidance processing and control system for tracking acarrier in the presence of clutter, wherein the carrier includes abeacon system for selectively transmitting and not transmittingradiation based on remote control signals, said processing and controlsystem capable of tracking the carrier in conjunction with a sight andelectronics of the type which outputs frames of video data based onenergy emanating from a scene that includes the carrier, said processingand control system positioned off the carrier and comprising:inputcircuitry adapted to receive segments of video data for tracking thecarrier; output circuitry adapted to provide guidance signals andcontrol signals for the carrier; a storage medium containinginstructional information in the form of binary data; and processingcircuitry, connected to said input circuitry, said output circuitry andsaid storage medium, for operating on segments of video data withinstructional information derived from the binary data to (a) eliminatepeaks in a first segment of data which correspond to peaks present in asecond segment of data based on an initial comparison between segments,and (b) provide a control signal to said output circuitry forselectively transmitting radiation from the beacon system to the sightin order to track the carrier. .Iaddend. .Iadd.37. The system of claim36 wherein selective transmission of radiation from the beacon system tothe sight is effected with an interrupt signal to prevent transmissionand thereby prevent a frame of video data from including a peak whichcorresponds to the carrier. .Iaddend. .Iadd.38. The system of claim 36wherein each segment of video data corresponds to a portion of adifferent frame. .Iaddend. .Iadd.39. The system of claim 36 wherein theprocessing circuitry, in cooperation with the instructional information,provides signals to control the beacon system for selectively nottransmitting radiation to the sight in order to identify as clutter apeak remaining in the first segment of data after one or more otherpeaks are eliminated on the basis of the initial comparison. .Iaddend..Iadd.40. The system of claim 36 formed as:an electronics packagecomprising a microprocessor and adapted for coupling to the sight; and acontroller which controls launching of the carrier, activation of thesight and the initial comparison between segments of data. .Iaddend..Iadd.1. In a carrier tracking system for detecting, tracking andguiding a carrier to a destination, a beacon control system positionableon the carrier for receiving control commands from a remote source, saidbeacon control system comprising:input circuitry responsive to controlsignals originating off the carrier for selectively transmitting and nottransmitting radiation to a location off the carrier. .Iaddend..Iadd.42. The system of claim 41 further including an electromechanicalshutter system operatively coupled to the input circuitry for effectingselective transmission of the radiation in response to the controlsignals. .Iaddend. .Iadd.43. The system of claim 42 wherein the shuttersystem, when mounted on the carrier, is responsive to the controlsignals to blank out the radiation with respect to the location off thecarrier. .Iaddend. .Iadd.44. In a carrier tracking system for detecting,tracking and guiding a carrier, of the type which includes inputcircuitry for receiving guidance commands from a remote source, a beaconsystem positionable on the carrier and responsive to control signalsoriginating off the carrier for selectively varying transmission ofradiation to a location off the carrier. .Iaddend. .Iadd.45. The systemof claim 44 wherein the beacon system comprises an electromechanicalshutter system operatively coupled to the input circuitry foralternately transmitting radiation in response to the control signals..Iaddend. .Iadd.46. In a carrier tracking system for detecting, trackingand guiding a carrier to a destination, a carrier comprising:inputcircuitry for receiving control signals from a remote source; and abeacon system responsive to said control signals for selectively varyingtransmission of radiation to a location off the carrier. .Iaddend..Iadd.47. The carrier of claim 46 wherein the beacon system includes alaser responsive to said control signals to alternately transmitradiation to said location. .Iaddend. .Iadd.48. In a system fordetecting, tracking and guiding a carrier to a destination, a carriercomprising: input circuitry adapted to receive guidance commands forguiding the carrier and control signals from a remote source; and abeacon system in electrical communication with said input circuitry andresponsive to receipt of said control signals by said input circuitry toselectively vary transmission of radiation to a location off thecarrier. .Iaddend. .Iadd.49. The carrier of claim 48 wherein the beaconsystem operates to provide information to said remote source whichdistinguishes the carrier from clutter. .Iaddend. .Iadd.50. The carrierof claim 48 wherein said remote source operates in conjunction with athermal night sight for viewing the carrier and wherein the beaconsystem provides information through the night sight to said remotesource to distinguish the carrier from clutter. .Iaddend. .Iadd.51. Thecarrier of claim 48 wherein the carrier is a guided missile. .Iaddend.